Wasn't the first frequency used in North America 25 HZ? At 25Hz, they
could see the
flicker in a ordinary light bulb and they used this to synchronies
another generator when
they wanted to supply more power to the line. Perhaps 50Hz came by just
doubling 25 Hz.
Now how did we get 60 Hz?

> ----------
> From: Martin R. Green[SMTP:spam_OUTelimarTakeThisOuTNOSPAMBIGFOOT.COM]
> Sent: Wednesday, January 28, 1998 11:07 AM
> To: .....PICLISTKILLspam@spam@MITVMA.MIT.EDU
> Subject: [OT] Re: off topic
>
> I don't know why, but I do know it hasn't always been this way. Years
> ago the standard voltage was 110V, then for some reason it was upped
> to 112V, then 115V, then 117V, and now 120V.
>
> As for the frequency, many such decisions were completely arbitrary in
> the early days of electricity. I do know it is easier to filter than
> the 50Hz used in Europe and elsewhere, and allows slightly smaller
> power transformers. My guess it relates more to available technology
> at the time than through a conscious decision. The choice of a power
> line frequency has affected the development of TV in the respective
> countries as well, since the vertical refresh rate was chosen to match
> the power line frequency to minimize interference.
>
>
> CIAO - Martin.
>
> On Wed, 28 Jan 1998 07:07:36 -0800, richard dellacona
> <richarddKILLspamEXPLORENET.NET> wrote:
>
> >hello out there does any one out there know why 60 cps and 120 vac
> >is used in usa for line voltage no one seems to know or have a good
> >answer for this question
>
>
> Martin R. Green
> .....elimarKILLspam.....NOSPAMbigfoot.com
>
> To reply, remove the NOSPAM from the return address.
> Stamp out SPAM everywhere!!!
>

>>flicker in a ordinary light bulb and they used this to synchronies
>>another generator when
>>they wanted to supply more power to the line.
>
>Professor Wiley Hartzog (Auburn U.) said they put a bulb between the two
>lines, and when it went out, they threw the knife switch to bring on the
>other generator.

Not one bulb, but two in series (because one will burn out immediately); the
normal way is to use six bulbs, two between corresponding fases of the two
generators; when all bulbs are out, you can put the second generator on the
distribution bars, because that way they are phase synchronized. Have done
myself this way with two hydro-powered 50 kVA generators somewhere in
Northern Argentina, in a small Andes-town...

> Not one bulb, but two in series (because one will burn out
> immediately); the normal way is to use six bulbs, two between
> corresponding phases of the two generators; when all bulbs are out,
> you can put the second generator on the distribution bars, because
> that way they are phase synchronized. Have done myself this way with
> two hydro-powered 50 kVA generators somewhere in Northern Argentina,
> in a small Andes-town...

Of course. Even if you use bulbs of a higher voltage, you want a bit
of leeway as if they burn out you could get the wrong idea. Two bulbs
in series are also used to allow testing between phases (three-phase
system presumed).

You didn't mention the reason of course for using the bulbs across all
three phases rather than just the first.